This invention relates to a hydrostatic controller for a vehicle power steering system of the type including a metering device having a rotor coupled to the steering drive shaft through which limited axial displacement is imparted to a rotatable valve element controlling the flow of fluid through the metering device to a servomotor and is related disclosure-wise to the subject matter in copending application Ser. Nos. 136,471, 147,583 and 147,601, respectively filed Apr. 2, 1980 and May 7, 1980, and owned in common by the same assignee.
The arrangement of longitudinal distributor grooves on the rotatable valve element associated with the foregoing type to hydrostatic controller, makes possible precision controlled distribution of pressure medium with minimal leakage losses from the fluid displacing pockets of the metering device and the pressure chambers of the servomotor. Such arrangements are disclosed, for example, in German Pat. No. 14 80 720 and in U.S. Pat. No. 3,937,601. In such prior art arrangements, the rotatable valve element is necessarily provided with a relatively thick wall since internal grooves are formed therein for coupling of the rotor gear of the metering device to the valve element through its internal bore in the region of the longitudinal distributor grooves aforementioned.
It is therefore an important object of the present invention to provide a rotatable controller of the aforementioned type having a compact construction and which may be fabricated at a reduced cost in a simpler fashion than was heretofore thought possible.